Limp mode

My ranger is in Limp mode, I originally had codes indicating low voltage at map sensor. Replaced faulty battery, slight improvement, indications led me to think vacuum leak. Smoke tested and 'start ya bastard' volatile spray round possible leak points test. Could find no problem. However, trimmed one hose and intake air hose, replaced squeeze clamps with worm drives, again, slight improvement, did have some absolute idiot {me}problems while trying to add new horn add, not replace. Caused smoke. Speedo and horn not working, replaced fuses, both working. Also replaced engine compartment fuses inj, alt, again, slight improvement. Changed oil, replaced fuel filter, cleaned map sensor, cleaned maf sensor, believe I have correctly replaced.I do all this for two reasons, no mechanic could suggest anything else except that it would cost thousands. Have tried to clear check engine light, not since replacing fuses, loses power under load, but not as much as before, however, if I prime the fuel pump 9 times out of 10 it goes like the clappers, I listened to injectors, sound even and same, this all indicates to me that 1, I do have a vacuum leak, 2. Faulty map sensor. The motor never went as well as it goes when it is running properly, is this because the fuel trim is overcompensating for high air values, that is higher readings than actual intake and I am getting a rich fuel mixture? Or will the limp mode go on its own when problem is fixed or could the only problem be that the light is still on and governing the pcm?I am an invalid pensioner, but quite happy to subscribe to membership after this question, as I intend to look after my own vehicle.